(Fdisplay_buffer): Doc fix.

src/window.c

@@ -1999,7 +1999,11 @@ If BUFFER is shown already in some window, just use that one,\n\
 unless the window is the selected window and the optional second\n\
 argument NOT-THIS-WINDOW is non-nil (interactively, with prefix arg).\n\
 If `pop-up-frames' is non-nil, make a new frame if no window shows BUFFER.\n\
-Returns the window displaying BUFFER.")
+Returns the window displaying BUFFER.\n\
+\n\
+The variables `special-display-buffer-names', `special-display-regexps',\n\
+`same-window-buffer-names', and `same-window-regexps' customize how certain\n\
+buffer names are handled.")
   (buffer, not_this_window)
      register Lisp_Object buffer, not_this_window;
 {